Method for the production of metallic powder in spherical form



Jan l 1946. E. H. E. JoHANssoN 2,391,903

METHOD FOR THE PRODUCTION OF METALLIC POWDER IN SPHERICAL FORM Filed March 1'7, 1944 Patented Jan. l, 1946 METHOD FOR THE PRODUCTION (BF METAL- LIC PUWDER IN SPHERICAL FRM Erik Harry Eugen Johansson, Stockholm, Sweden Application March 17, 1944, Serial No. 527,008 lin Sweden November 29, 1940 (Cl. 'l5-0.5)

4 Claims.

Iron and other metal powders have been made by electrolysis of solutions of metal salts. This method yields sharp-edged powder grains which, in some instances, particularly in the case of iron powder intended for use in the production vof socalled loading coils, have disadvantages. In order to avoid the production of such sharp-edged grains, powders have been made by the reduction of :metal salts by means oi zinc dust and aluminum.

Since it is very dimcult and practically impossible to produce metallic powder in pure form-particularly iron powder-by means of zinc dust and since it is too expensive to produce the same by means of aluminum, another method for the production of spherical powder 'of iron, nickel, chromium and other similar metals is desirable.

The present invention relates to such a method in which the indicated drawbacks are eliminated.

. According to the invention one electrolyzes with an anode which consists of, or contains, the metal to be produced in powder form, a, salt melt containing as cation or cations a less noble metal,

' such as zinc, cadmium or an alkali or alkaline earth metal, which metal in gaseous form is to participate in the final reaction, and as anion or anions'one or more negative elements, preferably of the halogenrgroup, capable of forming salts with the anode metal. The gaseous metal and the gaseous salt formed during the electrolysis are caused to react witheach other in a, separate chamber thereby reforming the metallic salt used as electrolyte.

In order to reduce the costs of the powder production one can, according to the invention, `prei!- erably proceed in such a way that one electrolyzes a melt consisting for example completely or substantially of a. mixture'of chloride o! potassium and bromide of potassium, between an anode consisting of or containing the metal the powder of which is to be produced, and a cathode preferably consisting of the same metal or an alloy thereof. The halogen salt formed at the anode as well as the alkaline metal disengaged at the cathode are admitted into a separate chamber in which reaction takes place betweenv them thereby reforming the alkali or alkaline earth metal halogenide and forming the pulverulent anode metal. The process is rendered completely automatic by suitable construction of the apparatus.

Apparatus suitable for carrying out the process is diagrammatically illustrated in the accompanying drawing which is made self explanatory by the legends thereon.

Having now described my invention, what I claim as new and desire to secure by letters Patv ent is:

1. Method of producing metallic powder in ing, using an anode comprising the metal to be powdered, a salt melt electrolyte comprising a less noble metal anion and a cation capable of forming a volatile salt with the metal to be powdered thereby liberating vapor of said volatile salt at the anode and vapor of said less noble metal at lche cathode, mixing said vapors and separating and recovering the resulting powder of the anode metal and said electrolyte salt.

2. Method as defined in claim 1 in which the electrolyte comprises potassium chloride.

3. Method as defined in claim 1 in which the electrolyte comprises potassium bromide.

4. Method as deilned in claim 1 in which the anode comprises iron and the electrolyte consists 

